This invention relates generally to implement closures and, more particularly to protective closures for writing implements such as pens or pencils, being strikingly suitable for use therewith.
It is common practice, especially in pen design and construction, to provide a protective means to safeguard the writing tip when not in use and to prevent unwanted marking of unintended objects such as shirt pockets. A removable cap is commonplace, as are the somewhat more costly and complex writing implements having one of a variety of transmission mechanisms for moving the writing tip in and out of register with a protective barrel member.
Inherent drawbacks to the above methods include loss or displacement of the cap and mechanical failure, as well as higher manufacturing complexity and cost, of the transmission mechanism employed. Accordingly, it has been the purpose of several existing closure devices, and writing implements incorporating the same, to provide an alternative to both the removable cap and commonly employed transmission mechanisms as means for protecting and exposing the writing tip of a pen or pencil. Representative of such devices are Zepelovitch, U.S. Pat. No. 2,559,555 and Vogel, U.S. Pat. No. 3,311,089.
A typical alternative, as demonstrated in the Zepelovitch patent, is the axially displacable closure mounted upon the writing implement end in the vicinity of the writing tip. Meant to be carried and retained thereupon, the closure slides in its entirety from an advanced, covering position to a retracted, exposing position with respect to the writing end and tip. Additional members as keepers, controlling the extent of movement and preventing unwanted retraction or removal of the closure.
Another alternative, as demonstrated in the Vogel patent, is a contracting casing for housing a conventional writing element or cartridge therein. In this patent, a forward casing portion is adapted for axial movement toward a rearward casing portion, thereby outwardly projecting or otherwise deforming a flexible intermediate casing portion intended for this means. Being axially stationary therein, the writing means of the cartridge is projected beyond the implement through a forward opening. Additionally, according to Vogel, the achieved writing position is maintained by finger pressure transmitted through the forward casing portion to the writing cartridge, or is self-retained therein by frictional engagement between the forward opening and the cartridge member.
SUMMARY OF THE INVENTION
In the preferred embodiment, the present invention provides an implement closure, specifically a writing implement closure, that provides isolation and protection of the writing tip. A simply constructed tubular sheath is provided which is adapted for an adherent relation to the body portion of an ordinary writing implement. While being stationarily carried upon the body portion of the implement in the vicinity of its writing end, the closure provides both a normally closed or enclosing position and an achieved open or exposing position with respect to the writing tip. The closure is adapted to flexibly fold upon itself to achieve a cross-sectionally continuous and self-retaining fold, not only contracting the length of the closure thereby, but also retaining the closure in its open or exposing position.